1. Field of the Invention
The present invention generally relates to a seatbelt device for securing a passenger to a seat and ensuring the safety of such passenger, and particularly relates to a seatbelt device comprising a retractor for retracting and protracting a webbing with a power source such as a motor.
2. Description of the Related Art
A seatbelt device comprising a retractor for retracting and protracting a webbing has been conventionally known, for example, as described in U.S. Pat. No. 4,511,097. This typical seatbelt device proposes a combination with a motor for protracting and retracting the webbing.
However, if an emergency situation occurs (disconnection within the motor, for example) and a drive current cannot be supplied to the motor of the seatbelt device, no driving force or braking force will be generated, and it is possible that the motor will slip. In such case, after the webbing is fastened, the webbing can be protracted but will not be automatically retracted, and thus, the slack in the webbing is not removed. Driving a vehicle with a slack in the webbing is undesirable as the passenger""s security cannot be sufficiently ensured.
The respective controls mentioned above are performed uniformly without consideration to the different uses of the seatbelt by various passengers, and are not necessarily optimum for each passenger. Thus, a typical conventional passenger security/protection device for vehicles could not, in a sufficient manner, provide a comfortable seatbelt-wearing environment or appropriately secure and protect the passenger.
Although a seatbelt is for securing and protecting the passenger upon a vehicle accident, it is also desired that such seatbelt be disengaged immediately after the accident so that the passenger may escape from such vehicle.
Conventionally, when a vehicle accidentally went underwater, the passenger would remove the webbing from the buckle and open the door or window to escape from such vehicle. In this case, the passenger may instantaneously panic, and try to escape without disengaging his/her seatbelt, and the seatbelt device will therefore hinder the passenger""s escape. When a vehicle accidentally rolls over, also, the passenger may panic and try to escape without disengaging the seatbelt.
Upon rescuing a passenger from the rolled over vehicle, it is difficult to disengage the buckle of the seatbelt device as it is mounted on the central side of the vehicle interior. Thus, the webbing is often cut in order to rescue the passenger.
Thereby, for example, proposed in Japanese Patent Laid-Open Publication No. Sho 59(1984)-40964 is to provide a buckle disengagement device for automatically disengaging the buckle in order to let the passenger free. According to this structure, it is possible to disengage the buckle in emergency situations.
Nevertheless, if the buckle is disengaged due to a misdetection, the passenger must go through the trouble of reconnecting the tongue plate, which the webbing passes through, to the buckle.
The present invention was devised in order to resolve the aforementioned conventional problems and an object thereof is to provide a passenger security/protection device for vehicles capable of realizing a comfortable seatbelt-wearing environment as well as appropriately securing and protecting a passenger.
Another object of the present invention is to provide a seatbelt device capable of realizing the immediate escape or rescue of the passenger after a vehicle accident.
A further object of the present invention is to provide a seatbelt device capable of realizing extra safety and a swift escape of the passenger by protracting the seatbelt in accordance with the state of the vehicle accident.
In order to achieve the aforementioned objects, the present invention provides a seatbelt device comprising: a retractor which uses a motor for retracting and protracting a webbing that secures a passenger to a seat; and a controller for rotating the motor in order to at least retract the webbing; wherein the controller changes the protraction mode of the webbing in accordance with the state of the webbing fastened by the passenger.
The retractor comprises: a reel to which the webbing is wrapped around; a motor for rotating the reel via a power transmitting mechanism; a rotation detection element for detecting the rotation of the reel; a locking mechanism for locking the rotation of the reel in emergency situations; wherein, when the controller does not detect the rotation of the reel after supplying drive signals to the motor, the controller supplies activation signals to the locking mechanism ordering the activation of the locking mechanism.
When the webbing cannot be retracted with a motor, this structure minimizes the possibility of a passenger wearing a loose webbing (seatbelt) by preventing the protraction of the webbing.
The controller controls the drive of the motor and alters the protraction mode of the webbing based on at least one condition among the slack, tension and retraction power of the webbing, and vibration pattern of the webbing for determining the generation of an alarm.
The controller comprises an alteration element for altering, in accordance with the state of webbing fastened by the passenger, at least one condition among the slack, tension and retraction power of the webbing, and vibration pattern of the webbing for determining the generation of an alarm.
According to this structure, since at least one condition among the slack, tension and retraction power of the webbing, and vibration pattern of the webbing for determining the generation of an alarm is altered in accordance with the state of webbing fastened by the passenger, it is possible to provide a comfortable seatbelt-wearing environment and to appropriately secure and protect the passenger.
Moreover, the seatbelt device according to the present invention may further comprise an adjustment element for adjusting the contents altered by the alteration element.
Even if the contents altered by the alteration element do not suit the passenger, this structure enables the adjustment of such altered contents with the adjustment element. Thus, it is possible to provide an optimum seatbelt-wearing environment for each passenger and to appropriately secure and protect the passenger at all times.
The seatbelt device according to the present invention may further comprise an accident detection element for detecting the state of the vehicle accident, wherein the controller alters the protraction mode of the webbing with a motor in correspondence with the state of accident.
With this structure, it is possible to secure the passenger to his/her seat upon removing the slack in the webbing before the accident, and to loosen the webbing in an appropriate timing in correspondence with the state of the vehicle after the accident. Thus, this is preferable as the passenger""s safety and ease of escape are provided.
The locking mechanism may include: a mechanical locking mechanism for mechanically locking the rotation of the reel; and at least (a) webbing acceleration sensor for activating the mechanical locking mechanism in correspondence with a sudden protraction of the webbing; or (b) a vehicle acceleration sensor for activating the mechanical locking mechanism upon considerable deceleration.
The webbing acceleration sensor and vehicle acceleration sensor may respectively comprise an electromagnetic actuator for compulsorily activating the mechanical locking mechanism in correspondence with the supply of activation signals.
The controller may be structured so that it does not activate the electromagnetic actuator when the reel is rotating due to the passenger protracting the webbing.
With this structure, it is possible to prevent the hindrance of the protraction of the webbing necessary for fastening the webbing.
The electromagnetic actuator may include: a mechanical urging element for providing a mechanical urge to the actuator in order to activate the webbing acceleration sensor or vehicle acceleration sensor; and an electromagnetic force generating element for generating electromagnetic force which suppresses the mechanical urge; wherein the electromagnetic actuator maintains the electromagnetic force in a stationary state.
Even if the power source to the motor or seatbelt device is cut off due to some problem, this structure activates the mechanical locking mechanism of the reel (i.e., webbing) with the mechanical urging element upon the termination of the electromagnetic force. Thereby, the locking of the webbing is secured even if irregularities occur to the electrical system.
The rotation detection element may be structured from a potential meter connected to the reel.
With this structure, it is possible to learn the rotation quantity from the standard position and estimate the protraction quantity, retraction quantity, rotation quantity of the reel (reel shaft), etc.
The controller is also capable of protracting the seatbelt with the motor after a predetermined time elapses from the detection of the accident.
The accident detection element comprises a drowning detection element for detecting that the vehicle has drowned, and the controller is capable of rotating the motor in the protracting direction in correspondence with the detection of this drowning.
The detection element comprises a rollover detection element for detecting that the vehicle has rolled over, and the controller is capable of rotating the motor in the protracting direction in correspondence with the detection of this rollover after a predetermined time elapses.
The predetermined time may be set to a time required for the abatement of the impact incurred to the rolled over vehicle.